Keep off the grass!

Chopper drivers all prefer to go one way rather than the other. Many profess to he happy to blow both ways but they always have a secret preference. Logic suggests blowing to the right make sense as the controls are all on the right of the cab so the driver is already leaning that way; but equally tradition leads us to go clockwise round a field with the trailer then on the left.

Do you load to the left or to the right?

Does it make any difference?

Of course it doesn’t, it makes no difference at all. But what does matter is where the trailer and its tractor are putting their tyres. Come to that, where everything other than the chopper is putting its tyres is really important.

So let look at why it matters where you drive. To turn the grass into silage, we need those lactobacillus bacteria to do their stuff and convert some of the grass sugars into lactic acid in the clamp. Everything you are doing to harvest the crop is based around keeping these guys happy and giving them the best conditions to thrive. So why does it matter where you drive?

 It matters because the good bacteria are already there ready and waiting on the silage crop as it’s sitting in the swath. On the soil just below them are billions of other bacteria that you really don’t want in your silage. Luckily the crop stubble keeps the swath off the soil and out of harms way. As soon as you drive on the crop you produce two issues.

Firstly the tyres have been running on the stubbles and will have come into contact with the soil so any bacteria on the soil with will be passed onto the crop in the swath. This is to be avoided, if at all possible, as it will increase the time it takes for the lactobacillus bacteria to become dominant in the clamp and that leads to increased losses – losses you can’t see and will only ever see in the bank account.

Does it matter if you run on the grass?

My tyres are clean so its OK to run on the grass isn’t it?

Well there is clean and there is bacteria free and no your tyres are not bacteria free. But even if the tyres were clean and only ever ran on the crop so didn’t pick up anything off the soil, it would still matter. So far we have only considered tyres contaminating the top of the swath, but the tyre is also pressing the crop down onto the soil surface so the underside of the swath is being contaminated with bacteria.

 I’m using inoculant additive so driving on the crop isn’t a problem

As we have seen elsewhere in this series, additives and inoculants in particular can only increase the chances of making better silage. To be honest, if you are using additives and still driving on the crop – you are wasting your money. Stop driving on the crop and you can consider not spending cash on that million pound a tonne powder.

So how can you manage traffic to minimise running on the crop?

The easy bit is where the trailers run - keep the trailers on the cleared land, on the outside for the headlands. On the first run that is more difficult unless you are running behind a really wide rake, but once the land is opened up it’s easy to control the traffic. So that’s the easy bit, the operations ahead of the chopper are more difficult to keep off the crop. If you are spreading grass out after mowing then obviously the rake is going to have to drive on the spread crop to put it back into a swath and there’s nothing you can do about that other than clean the kit before it heads off to the fields. If you are spreading swaths for wilting or pulling swaths together then the tractor wheels need to be running on the cleared ground rather than the swath. This makes selecting the right tedders and rakes a bit more difficult as the machines need to follow the mower swaths. Treat this like growing cereals on tramlines and gear up to suit your traffic system.

The problem is the headland, and there is no way to avoid driving on the crop at either end of the field and this applies for all the kit from mower to rake. A direct crossing of a swath on the headland will limit contamination to an absolute minimum but in some case we can do more. When harvesting on really wet ground, perhaps after a very wet spring, then the issues of contamination are much more important. Really bad cases of contamination can lead to losses in the clamp that you can actually see.

Faced with really difficult conditions you might be wise to cut and clear the headlands first before tackling the body of the fields. The crop from the headlands may be baled or zero grazed to ensure the main area of silage is made and stored in a timely manner.

 If you want to discuss how you can minimise soil contamination and trafficking with an independent consultant or to discuss any of the other aspects of silage making covered in this series – contact Jeremy Nash @ Jeremy@silageconsultant.co.uk